1. Field of the Invention
The present invention relates to a fluid device connecting structure for coupling first and second fluid devices with a connection member, and a fluid device unit.
2. Description of Related Art
Heretofore, in a semiconductor manufacturing process, a liquid crystal manufacturing process, etc., various fluid devices have been used for control of chemical liquids. For example, the fluid devices may include valves such as a flow rate control valve and an opening/closing valve, filters, sensors such as a pressure sensor and a flow rate sensor, and piping blocks such as a joint block and a passage block. Recently, connection parts of those fluid devices are directly connected to each other with a coupling member to form an integral unit for a compact apparatus.
FIG. 45 is a sectional view of a conventional fluid device connecting structure 1100.
This conventional fluid device connecting structure 1100 is arranged such that first and second fluid devices 1101 and 1102 have connection parts 1103 and 1104 formed with seal grooves 1105 and 1106 respectively, between which a seal member 1107 is fitted, and a coupling member 1108 is mounted on the periphery of connecting portions of the connection parts 1103 and 1104.
The coupling member 1108 includes a cylindrical nut 1109 and a split ring 1110. The cylindrical nut 1109 has a cylindrical shape with one open end. The other closed end is formed with an insertion hole 1109a in which a protrusion 1104a of the connection part 1104 is inserted. The split ring 1110 has an annular shape including an inner surface that contacts an outer surface of the connection part 1104 and an outer surface that contacts an inner surface of the nut 1109. This ring 1110 is constituted of a plurality of split pieces so as to be mounted on the outer surface of the connection part 1104.
The coupling member 1108 is mounted in such a way that an end of the connection part 1104 of the second fluid device 1102 is inserted in the nut 1109 through the insertion hole 1109a, then the nut 1109 is displaced toward the second fluid device 1102 to expose the connection part 1104 as shown by a dashed line in FIG. 45, and then the split ring 1110 is fit on the outer surface of the connection part 1104. After that, as shown in a solid line in FIG. 45, the nut 1109 is slid toward the first fluid device 1101, internal threads 1109b formed on an inner surface of the nut 1109 are engaged with external threads 1103a formed on an outer surface of the connection part 1103 of the first fluid device 1101. The nut 1109 is screwed on the connection part 1103 until the split ring 1110 abuts on the protrusion 1104a of the connection part 1104. This screw feed allows the seal member 1107 to be fitted in the seal grooves 1105 and 1106, thus sealing the connecting portions of the connection parts 1103 and 1104 (for example, see JP2006-64080A).
However, to mount the split ring 1110, the conventional fluid device connecting structure 1100 needs a space for allowing movement of the nut 1109 and a space for screwing the nut 1109 on the connection part 1103. This would require troublesome works and working space for coupling the fluid devices. Accordingly, when the conventional fluid device connecting structure 1100 is applied to a semiconductor manufacturing apparatus in which a number of fluid devices are arranged in complicated pattern, a space for sliding or screwing the nut 1109 on the connection part 1103 could not be ensured. It would take much time to screw the nut 1109 on the connection part 1103 properly to provide predetermined sealing strength.